In a survey conducted by the National Headache Foundation (NHF), three out of four people who had frequent headaches reported weather or barometric pressure changes as triggers.

A similar number said they avoided bars or clubs to limit their exposure to cigarette smoke, 51% reported being unable to attend concerts with loud music, and 38% said they limited their time at the computer -- all in an attempt to keep headaches from happening.

The survey was designed to identify the environmental factors considered by patients to be major headache triggers.

In addition to weather and altitude changes, bright or flickering lights, strong odors, cigarette smoke, and loud music were frequently cited as triggers.

NHF Executive Director Suzanne E. Simons says people often have trouble identifying their own headache triggers because a combination of factors may be involved.

"It can take a lot of detective work, and that is why keeping a headache diary is so important," she tells WebMD. "A headache diary kept over a three-month period can be one of the best tools your physician has for making an accurate diagnosis."

Blame It on the Rain

About 28 million Americans suffer from migraine headaches, with 25% of women and 8% of men experiencing one or more migraines over the course of a lifetime.

In the survey of nearly 200 frequent headache sufferers, about one out of three reported limited travel because of headaches.

Seventy-four percent said their ability to participate in outdoor activities had been restricted because of changes in weather, altitude, high winds, or bright lights.

Atlanta-based neurologist Leslie Kelman, MD, tells WebMD that it is not clear how weather changes might trigger headaches, but some research suggests that they do.

In one study reported in 2004, researchers compared headache calendars kept by patients who believed weather played a major role in their headaches to weather data from the National Weather Service.

They concluded that while it appeared that weather variables may have a link to headaches, more patients thought weather was a trigger than was the case.